Audi to Begin Production of Next-Generation Diesels in 2008; Bin 5 and Beyond

18 July 2007

Audi announced that it will begin production of a new generation of TDI diesel engines in mid-2008. The new diesels will use an optimized combustion process and an ultra-low emission system to comply with US EPA Tier 2 Bin 5 requirements as well as future European standards.

In making the announcement about its new diesels, Audi also touched on its other efforts to improve vehicle efficiency and reduce CO2 emissions, including the development of a power management system with regenerative braking; a new start-stop system; selective hybridization for certain markets; and its backing for alternative fuels such as Biomass-to-Liquids (BTL) diesel and compressed natural gas.

The first of the new 2008 diesel engines will be three-liter V-6 units for the Audi A4 and Audi Q7. These engines will develop 176 kW (240 hp) and deliver peak torque of 500 Nm (369 lb-ft) in the Audi A4 and 550 Nm (406 Nm) in the Audi Q7.

Additional models will follow in rapid succession, with Audi seeking to extend the new technology to other vehicle classes and power categories by 2010.

We intend to consolidate the status of the TDI as a highly efficient form of propulsion on a sustained basis. And in future we will be launching ‘e’ model variants designed for optimised fuel consumption in the high-volume model series—either in TDI guise or as petrol models with state-of-the-art TFSI technology.

—Rupert Stadler, Chairman of the AUDI AG Board of Management

The new diesels will feature a new piezoelectric common-rail system with an injection pressure of 2,000 bar. Combustion chamber sensors will enable more precise regulation of the combustion processes. A combination of efficient exhaust gas recirculation and optimized turbocharging will deliver a sharp reduction in engine-out emissions.

A downstream urea SCR aftertreatment system will reduce emissions of oxides of nitrogen (NOx) by up to 90%. The emission system comprises the catalytic converter, the metering module, an AdBlue tank and heated lines, as well as an extensive system of sensors. The emission control system is rounded off by a separate two-way catalytic converter and an electronically controlled diesel particulate filter.

Audi will market these new models in the USA and in Europe from the second half of 2008.

Power management and hybridization. Looking beyond the engine and aftertreatment systems, Audi is developing a power management system for both diesel and gasoline models that captures and stores energy during coasting and braking for use in vehicle electrical systems. Audi is also developing a start-stop system for its vehicles. These approaches are similar to the actions BMW is taking across its 1, 3 and 5 Series models. (Earlier post.)

Audi is developing hybrid systems for a number of its models and says that it will put them into series production wherever it sees this as producing significant benefits for customers.

Audi unveiled the Audi Q7 hybrid study with an electric motor integrated into the driveline between engine and gearbox in 2005. (Earlier post.)

Fuels. In addition to its backing for BTL diesel in the form of the SunFuel facilities backed by the Volkswagen Group, Audi noted that it is developing a CNG engine based on the TFSI gasoline engine.

The CNG concept is retains its performance even when running in natural-gas mode, and offers a reduction in CO2 emissions of up to 20%. The placement of the natural gas storage tank still allows full use to be made of the luggage compartment.

perhaps Audi figures that the SCR system is so expensive, they can only achieve the desired profit margin if the diesel option is at the top of the power range on offer.

Like its competitors, Audi is currently churning out new engine designs at a high rate. They've just done a bunch of inline fours, so the V6s are probably just the next in line. If diesel LDVs capture significant market share in the US, expect manufacturers to offer lower displacement engines with NOx store catalysts as well before long.

Right patrick, because OFFERING a powerful engine in a small/mid-size car to, you know, sell them, is absurd.

Some things to consider - the V6 is a showpiece Audi TDI engine, and something that makes logistical sense for US certification, i.e. if they had to choose ONE engine to offer first, it makes a great choice. Also, Audi is using the marketing angle of power/performance AND economy. Coming out with a lower-powered TDI off the line wouldnt make as big an impression with an ignorant American buying public. A 3.0L TDI A4 will still get mid-upper 30s mpg no problem, quattro or not, and be a very quick car. MPG well in the 40s on the highway is quite probable.

This V-6 will outperform the 4cylinder TFSI engine, I'm sure. On the other hand it doesn't even come close to the performance of the S4 and especially the RS4.

Their "showpiece" engine is a 4.2L V-8.

So are they selling it on the premise of power or fuel economy? 240hp is far shy of the S4 and even lower than the standard 3.2L V-6 FSI (255hp)...I bet the mileage is only marginally better than the 2.0L TFSI motor with all the emissions equipment added on, but who knows until they actually produce it.

Several European car magazines have reviewed the 3.0 TDI A5 and compared it favorably with the S5. The robust torque (369 lb-ft) allows it to go 0-60 in 5.9 seconds, compared to 5.1 for the S5, and the driveability of the TDI for accelerating out of corners has led some reviewers to say that they had little trouble keeping up with the S5 on winding roads--as far as acceleration is concerned.

Peter, the standard gasoline (naturally aspirated) 3.2L FSI engine in the A5 gets 0-60 in 6.1seconds. Almost the same performance as the TURBOCHARGED 3.0L V-6 diesel.

5.9 sec vs 5.1 sec probably translates to a 1.5 to 2 second difference in 1/4 mile times (especially considering the hp difference which matters greatly at high speed).

Winding roads do not equal racing on a track. What were the lap times and what track did they do the performance testing on (so we can see how long the track is and whether it has more turns or straights.) If they didn't test them on a race track its too subjective for me...even on a race track there are many variables but atleast some are mitigated.

It looks like the A5 TDI may get ~33mpg (euro mixed cycle) according to their UK website, but that is not a Tier 2 Bin 5 engine (maybe a 10-15% hit on efficiency for emissions equipment?).

Patrick: Audiworld.com says
"We also spent time behind the wheel of the Euro-spec A5 3.0-liter TDI and it is a clear winner. It appears able to keep up step-for-step with the S5, yet offers significantly improved fuel economy. It also provides a much flatter torque band which starts incredibly low in the RPM band." In their A5/S5 forum, an entry mentions that Autocar.co.uk says that the 3.0 TDI is the pick of the bunch. These are enthusiast sites that are probably more concerned with real world performance. I'm not aware of track performance reviews at this time. Anyone?

Patrick, You really seem to be having a hard time understanding the value of these engines. Perhaps you need to test drive one, or test drive what you think is a fast car, on public streets, against one. Equating street performance only to 1/4mi or race track times is silly. The TDI offers economy AND performance. It's not a compromise. And the 15 peak hp deficit vs the standard will NOT be missed by anyone I assure you, while getting substantially better economy. There is no way the 3.0TDI will give only marginally better economy than a 2.0TFSI. For identical displacements, I'd imagine an easy 35-45% better mpg; for 50% more displacement, probably still around 20-25% better no problem, with plenty more power.

I imagine a 3.0L TDI A4 will get mid 30s in mixed driving. 10-15% economy hit from the emissions controls needed for current 50 state sale?? In MPG? Where do you come up with that?? There's no way there's going to be that much loss. A little perhaps, 2-3% or so, but not 10-15%.

You're an odd one. So, to you, it's either or, eh?? Why are you comparing to an S or RS? Nobody, not Audi, not anyone, is expecting this to compete with those packages. Gee, a 3.0L V6 in a small-/mid-size sedan - what are they thinking?! It's an engine option. It's a desirable package. Why you can't see that, I cannot comprehend.

I say that it is more engine then is needed...someone says it is for performance, I respond that it doesn't even come close to the performance of the "real" performance models from Audi. How is it that difficult to follow the conversation that I have to recap it?

The comparison to the S model was also working under the assumption that the premium for diesel would put it closer to the price of the S model but apparently, in the UK at least, the 3.0 TDI is the same price as the 3.2FSI.

"The initial and 1950-hour estimated reductions in NOX, carbon monoxide (CO), and PM emissions due to the ECS were all statistically significant, as was the reduction in fuel economy (initially 18.7% relative to engine-out without EGR and 16.7% relative to engine-out with EGR)."
http://www.nrel.gov/vehiclesandfuels/apbf/pdfs/39228.pdf
page 9 for your viewing pleasure.

joe blow seems to "image" a lot of things.
If you're going to compare things, let's keep these discussion to real testing numbers, not what people imagine or wish or feel (nor how they got 60mpg one this one drive).

The bottom line is that gas engines are becoming more efficient, while diesel is becoming less efficient (due to the fact that they finally have to clean up those bad emissions).
Yes, diesels have a significant MPG or l/100km advantage, but that advantage is much smaller when you look at CO2 emissions (which corrects for the higher carbon density of diesel fuel). European efficiency regulations are shifting towards CO2, and that along with decreasing diesel subsidies, will make diesels less popular (but they'll always some good appliations).

However I support all clean high efficiency technologies. There's nothing wrong with working on multiple ways of doing this (diesel, fuel cell, hybrid, etc) because there is no one single best answer that will solve all problems for all applications. For example, if diesel was really the answer, why else would diesel proponents like VW and Audi be working so hard on improving gas engines ?

The bottom line is that everything in the near future is going towards hybrid (and later EV). Diesel, gas, fuel cell, hydrogen, plug in, etc... they'll all become hybrids of some sort. It just doesn't make sense not to recover braking energy and to have cars idle while stopped.

Again, Patrick, by your logic there should ONLY be two engines in any vehicle - pure economy version and outright performance version. NOBODY would agree with that.

The only issue of argument here is how much of an impact the emissions equipment will have on economy. I contend 10-15% is a gross overestimate.

I did a cursory review of that document. It doesnt give much detail on their economy determinations. I may read it over more later. A few points: 1) that's a fairly large vehicle/engine, not very comparable to many of the light duty diesels expected. 2) It would be remarkable for auto makers, especially European ones, to gamble so heavily on diesel with those sorts of losses on economy. 3) There are reports coming in regarding test examples of the new VW Jetta TDI with US-spec emissions gear, getting well over 50mpg. No previous US diesel Jettas got that kind of mileage in "normal" driving. Best I can give you for evidence (it's not the only evidence) - scroll down a ways: http://forums.vwvortex.com/zerothread?id=3327247&page=1

I don't see how the new vehicle could be getting better mileage than ever and be seeing 10-15% decrease in drivetrain MPG. Granted, the new Jetta TDI won't use SCR, but it's similar, plus I do expect diesel NOx emissions tech will be changing/improving.

Beyond that, logically, there arent that many reasons/sources for a 10-15% hit in MPG. There is DPF and there is NOx reduction. Depending on application, regeneration of either/both may require some excess fuel (generally to raise exhausts temp), but everything I've ever seen suggests it's a very small amount, every so often, and depends on driving conditions. The only other source of extra fuel consumption would be due to increased exhaust system back pressure. So, logically, I don't see how these aspects will decrease MPG by 10-15%. The 2-3% number is a guess, out of my mechanical engineering ass. And I stand by it - I imagine perhaps worst case 5%.

I suppose in about 6-12months, we'll know for fact. I'm not expecting much losses. I'd stake a lot on that.

Additional points: difference in energy content for diesel gas is about 10% - the difference in CO2 emissions is NOT "much smaller" due to this.

Diesels will see less subsidy in europe mostly because they no longer need it. Also, theyre popularity will continue to rise because they are simply the better solution for all but inexpensive economy cars (where a cheap naturally aspirated gas engine works).

BTW, near-future Audis will now incorporate "mild" hybrid tech for capturing braking energy. Combined with diesel, there's little need for any more hybridization other than option to operate in purely EV mode (plug in operation capability). I'm a mechanical engineer. I would be willing to wager anything that EV will not be mainstream for at least 20-30 years. We are entering the "diesel age." Diesel will dominate the next several decades, gas will be relegated to inexpensive vehicles and sports cars, and hybridization will work where it's cost effective. If you look at Audi's mild hybridization plans, they should be able to do regenerative braking for a tiny fraction of the cost of full hybrid such as Prius.

As an owner of a stock 2006 Jetta TDI I can tell you that I'm happy with the real-world driving performance, handling, and fuel economy (averaging 17.5 km/l or -- 41 mpg or 5.5 l/100km -- over 91000 km). My one complaint is off-the line acceleration, especially over 60 km/h, when the turbo spools off and the motor's torques (130 ft-lb) and horsepower (100 HP), shows itself.

If I had the money and skill to do it, I would put in a parallel hybrid system -- in-wheel electric motors for the rear -- as a performance boost and use the diesel for open-highway driving. (As it is, the car's MFD reports the motor consumes ~0.4 l/h at idle; so, shutting the motor off isn't critical.)

My choice for electrics are the PML HPD40's -- 2 each at 120 kW for a 320 HP boost... Mmm, mmm, toasty!

TORQUE is king! Why are you guys talking hp figures? HP means nothing in diesel speak. At 369lb ft the A4 TDI will probably stomp on the little S4 in most respects in around town power delivery. The torque delivery in a diesel is from the basement up to about 3K rpm. The way to effectively transmit it is through a DSG transmission.
I am one of those awaiting the Audi TDI's. I have owned Audis for about the last 15 years but am now forced into a 2006 Jetta 2.0TDI DSG. My Jetta has a REVO chip and is a monster off the line. When you shift quickly at around 2500 rpm intervals there is not much that will touch this thing from 0-30 mph. It is a very effective city car that returns 35mpg on non taxable 100% Bio-diesel.